An agricultural harvester (100) comprises a self-propelled vehicle (102); a feederhouse (104) disposed on the front of the self-propelled vehicle (102); a driveshaft (114), the driveshaft (114) having a proximal end supported for rotation on the feederhouse (104) about an axis of rotation, the driveshaft (114) having a distal end that is extendable from the proximal end; and a first coupler (116) fixed to the distal end, said first coupler (116) being configured for engagement with a second coupler (118), said second coupler (118) being disposed on an agricultural harvesting head (106) to drive a reciprocating knife of the agricultural harvesting head (106).